Embodiments of the invention relate generally to surface mounting technology utilized to electrically and physically interconnect electronic components. In surface mount technology (SMT), two surfaces may be electrically interconnected using solder bumps or balls that are deposited upon one of the surfaces and then reflowed or heated to solder the two surfaces together. SMT may be an advantageous process because it may not be necessary to work in the region between the two surfaces to be joined and because a large number of components may be connected in the same reflow step.
Sometimes, for example in the case of electro-optical components, it may be desirable to vertically bond (i.e. mount on its side) a component to a substrate. FIG. 1 is an example of vertical bonding a component 100 to a substrate 102. The component 100 may be a laser, a photodiode, or any component to be vertically mounted. In this case, the component is an opto-electrical component which may typically comprise a metal layer 104, a dielectric layer 106, and a transparent glass or plastic portion 108.
During fabrication of the component 100, the metal layer 104 may be the bottom of the component 100 and the glass/plastic layer 108 may be the top. The bottom metal layer 104 may comprise a corner bonding pad 110 projecting upward from the metal layer 102 near the top edge of the component 100. The pad 110 may be for making electrical connections as well as mechanical attachment via a solder bump 112 to the substrate 102 when the component 100 is flipped on its side, as shown.
While one pad 110 is shown in FIG. 1, a plurality of such pads may be present to provide corner solder joint arrays used as a means to electrically interface with I/O, power and bias bumps, for example on a microprocessor package. Potential problematic issues of this type of solder joint and contact pad may be manufacturability compatibility with the standard flip chip process. For example, it may be difficult for a pick and place tool to automate the placement of the component on the substrate. Other issues may include proper solder reflow and self alignment difficulties. Mechanical robustness of the finished product and potential reliability issues may arise because the joint may be sheared off at elevated temperatures.